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Best Practices for AWS EC2 Auto Scaling Configuration

Matt Mickiewicz
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Amazon Web Services (AWS) provides a wide range of cloud computing services, including Elastic Compute Cloud (EC2) for scalable computing resources. EC2 Auto Scaling is a powerful feature that allows you to automatically adjust the number of EC2 instances in your infrastructure based on demand. In this tutorial, we’ll cover the basics of AWS EC2 Auto Scaling and provide step-by-step instructions on how to set it up.

Contents:

  1. Introduction to AWS EC2 Auto Scaling
  2. EC2 Auto Scaling Prerequisites
  3. Creating an EC2 Launch Template
  4. Creating an Auto Scaling Group
  5. Configuring Scaling Policies
  6. Monitoring and Testing
  7. EC2 Auto Scaling Cheat Sheet

Introduction to AWS EC2 Auto Scaling

EC2 Auto Scaling helps you maintain the optimal number of instances in your infrastructure by automatically scaling the number of instances up or down based on demand. This ensures that you have enough resources to handle traffic spikes and reduces costs by releasing unneeded instances during periods of low demand.

There are three main components to EC2 Auto Scaling:

  • Launch Template: a configuration template that specifies the instance type, AMI, and other settings for the instances that will be launched.
  • Auto Scaling Group: a group of instances that share the same launch template and scaling policies.
  • Scaling Policies: rules that determine when and how to scale the number of instances in the Auto Scaling group.

EC2 Auto Scaling Prerequisites

Before we begin, make sure you have the following:

  • An AWS account with the necessary permissions to create and manage EC2 instances, launch templates, and Auto Scaling groups.
  • AWS CLI installed and configured with your AWS credentials.
  • A basic understanding of AWS EC2 and its components.

Creating an EC2 Launch Template

A launch template is a reusable configuration that specifies the settings for instances launched in an Auto Scaling group. To create a launch template, follow these steps:

  1. Sign in to the AWS Management Console and navigate to the EC2 Dashboard.
  2. In the left-hand menu, click on Launch Templates under Instances.
  3. Click the Create launch template button.
  4. Fill in the required fields, such as template name, description, and Amazon Machine Image (AMI) ID. You can find the AMI ID by searching for the desired instance type in the Instances section of the EC2 Dashboard.
  5. Choose an instance type, such as t2.micro or m5.large, based on your requirements.
  6. Configure additional settings, such as storage, security groups, and key pairs, as needed.
  7. Click Create launch template to save your configuration.

You can also create a launch template using the AWS CLI with the following command:

aws ec2-template --launch-template-name MyLaunchTemplate --version-description "Initial version" --launch-template-data '{"ImageId":"ami-0c94855ba95b798c7","InstanceType":"t2.micro","KeyName":"my-key-pair"}'

Replace the values for ImageId, InstanceType, and KeyNamewith your desired settings.

Creating an Auto Scaling Group

An Auto Scaling group is a collection of instances that share the same launch template and scaling policies. To create an Auto Scaling group, follow these steps:

  1. In the AWS Management Console, navigate to the EC2 Dashboard.
  2. In the left-hand menu, click on Auto Scaling groups under Auto Scaling.
  3. Click the Create an Auto Scaling group button.
  4. Select the launch template you created earlier and click Next.
  5. Choose a name for your Auto Scaling group and configure the desired VPC and subnets.
  6. Set the desired minimum, maximum, and desired number of instances for your Auto Scaling group.
  7. Configure any additional settings, such as load balancing and health checks, as needed.
  8. Click Create Auto Scaling group to save your configuration.

You can also create an Auto Scaling group using the AWS CLI with the following command:

aws Auto Scaling create-auto-scaling-group --auto-scaling-group-name MyAuto ScalingGroup --launch-template "LaunchTemplateName=MyLaunchTemplate" --min-size 1 --max-size 3 --desired-capacity 2 --vpc-zone-identifier "subnet-12345678,subnet-abcdefgh"

Replace the values for LaunchTemplateName, min-size, max-size, desired-capacity, and vpc-zone-identifier with your desired settings.

Configuring Scaling Policies

Scaling policies determine when and how to scale the number of instances in your Auto Scaling group. There are three types of scaling policies:

  • Target Tracking Scaling: automatically adjusts the number of instances based on a predefined metric, such as average CPU utilization or network traffic.
  • Step Scaling: increases or decreases the number of instances in steps, based on CloudWatch alarms.
  • Simple Scaling: increases or decreases the number of instances based on a single CloudWatch alarm.

In this tutorial, we’ll focus on target tracking scaling policies.

To create a target tracking scaling policy, follow these steps:

  1. In the AWS Management Console, navigate to the EC2 Dashboard.
  2. In the left-hand menu, click on Auto Scaling groups under Auto Scaling.
  3. Select your Auto Scaling group and click on the Scaling policies tab.
  4. Click the Create scaling policy button.
  5. Choose Target tracking scaling policy as the policy type.
  6. Enter a name for your scaling policy.
  7. Select a predefined metric, such as Average CPU utilization or Request count per target, and set the target value.
  8. Configure any additional settings, such as cooldown periods and instance warm-up times, as needed.
  9. Click Create to save your scaling policy.

You can also create a target tracking scaling policy using the AWS CLI with the following command:

aws Auto Scaling put-scaling-policy --policy-name MyTargetTrackingPolicy --auto-scaling-group-name MyAuto ScalingGroup --policy-type TargetTrackingScaling --target-tracking-configuration '{"PredefinedMetricSpecification": {"PredefinedMetricType": "ASGAverageCPUUtilization"},"TargetValue": 50}'

Replace the values for policy-name, auto-scaling-group-name, PredefinedMetricType, and TargetValue with your desired settings.

Monitoring and Testing

After setting up your Auto Scaling group and scaling policies, it’s essential to monitor and test your configuration to ensure it’s working as expected.

To monitor your Auto Scaling group, you can use Amazon CloudWatch to track metrics such as CPU utilization, network traffic, and instance counts. You can also set up CloudWatch alarms to notify you when specific thresholds are breached.

To test your Auto Scaling configuration, you can simulate traffic spikes or resource usage increases and observe how your Auto Scaling group responds. You can also manually adjust the desired capacity of your Auto Scaling group to see how it scales up or down.

Conclusion

In this tutorial, we covered the basics of AWS EC2 Auto Scaling, including creating launch templates, Auto Scaling groups, and scaling policies. By implementing Auto Scaling in your infrastructure, you can ensure that you have enough resources to handle traffic spikes and reduce costs by releasing unneeded instances during periods of low demand.

EC2 Auto Scaling Cheat Sheet

Component Description Options
Launch Template A reusable configuration that specifies the settings for instances launched in an Auto Scaling group. AMI ID, Instance Type, Key Pair, Security Groups, Storage, etc.
Auto Scaling Group A collection of instances that share the same launch template and scaling policies. Launch Template, VPC, Subnets, Min/Max/Desired Instances, Load Balancing, Health Checks, etc.
Scaling Policies Rules that determine when and how to scale the number of instances in the Auto Scaling group. Target Tracking, Step Scaling, Simple Scaling, Predefined Metrics, Target Values, Cooldown Periods, Instance Warm-up, etc.